Biomarker for Parkinson`s disease identified

Washington: Scientists have found that elevated levels of a protein can be detected in the skin of Parkinson's patients, offering a possible biomarker to help diagnose the disease early.

Researchers from Beth Israel Deaconess Medical Center (BIDMC) in US found increased levels of alpha-synuclein in the skin of Parkinson's patients.

The protein is found throughout the nervous system. Although its function is unknown, it is the primary component of protein clumps known as Lewy bodies, which are considered the hallmark of Parkinson's disease.

Currently there are no standard clinical tests available to identify Parkinson's disease, a neurodegenerative disorder.

"Even the experts are wrong in diagnosing Parkinson's disease a large percentage of the time," said senior author Roy Freeman, Director of the Autonomic and Peripheral Nerve Laboratory at BIDMC and Professor of Neurology at Harvard Medical School.

"A reliable biomarker could help doctors in more accurately diagnosing Parkinson's disease at an earlier stage and thereby offer patients therapies before the disease has progressed," Freeman said.

"Alpha-synuclein deposition occurs early in the course of Parkinson's disease and precedes the onset of clinical symptoms," said Freeman.

"Symptoms related to the autonomic nervous system, including changes in bowel function, temperature regulation, and blood pressure control may antedate motor symptoms in Parkinson's patients.

"Skin-related autonomic manifestations, including excessive and diminished sweating and changes in skin colour and temperature, occur in almost two-thirds of patients with Parkinson's disease.

"The skin can provide an accessible window to the nervous system and based on these clinical observations, we decided to test whether examination of the nerves in a skin biopsy could be used to identify a PD biomarker," he said.

To test this hypothesis, the research team enrolled 20 patients with Parkinson's disease and 14 control subjects of similar age and gender.

The participants underwent examinations, autonomic testing and skin biopsies in three locations on the leg. Alpha-synuclein deposition and density of cutaneous sensory, sudomotor and pilomotor nerve fibres were measured.

The results showed that alpha-synuclein was increased in the cutaneous nerves supplying the sweat glands and pilomotor muscles in the Parkinson's patients.

Higher alpha-synuclein deposition in the nerves supplying the skin's autonomic structures was associated with more advanced Parkinson's disease and worsening autonomic function.